Harry - I did the vacuum experiment years ago so details are a little hazy, but basically it was a jar with a small diameter (1/8" I.D. I think)tube sticking through the lid. Inside the jar was a small airfoil section made of modelling clay, suspended vertically with the tube pointing at the front/top surface. Basically like the spoon/faucet setup, but with an air jet instead of a faucet. Vacuum pump is high capacity relative to the small air inlet capacity, so when allowing air to flow in through the tube, the vacuum still stays fairly high - so all the significant air action is just the flow hitting the top side of the foil. The foil pulls into the airflow, just like the spoon in a water flow. And I'm pretty sure, mitigated by the absence of any real measurement, that the pressure on the top of the foil was mostly higher than on the bottom.
- Rick -----Original Message----- From: Harry Veeder [mailto:[EMAIL PROTECTED] Sent: Tuesday, December 06, 2005 5:43 PM To: [email protected] Subject: Re: OT: Secrets of bee flight revealed Rick Monteverde wrote: > Harry - > > I think the wedge effect is the bulk of a real wing's lift. Concurrent > with running a wedge through material, you get pressure differential. > But the cause of the differential is not from faster flow above than > below the curve, etc., it's just a wedge piling up compressible > material on its underside. Contributing also is reaction mass as I've > described, but I can't guess the proportion, and it no doubt varies > with reynolds number - but I think its usually significant. Lastly is > viscous drag on the reaction mass heading downward. I suspect that's > the smallest component on steady-state wings and may be costly in > terms of power spent, but comprises a large lift component in cyclic > wings. OIW "lift" is a composite from several sources in different > proportions depending on wing shape, angle of attack, Reynolds number, > etc. > > Agreed? > Almost.... I did the spoon-under-the-faucet experiment and it is very persuasive. However, could you please describe your apparatus with the vacuum pump in more detail. I am not intending to replicate the experiment, but I would like to know how you detected a lifting force. Thanks, Harry
